Kubomatsu Katsukiyo (1894-1941) - the 'great amateur'. Innovator in fuseki, teacher of a large group of pupils (including Kitani). Renju 8 dan, inventor of ninuki renju.
John Fairbairn MindZine article: http://www.msoworld.com/mindzine/news/orient/go/history/kubomatsu.html